SUMMARY/ABSTRACT Methodological advances now permit the use of genome-wide association studies (GWAS) to discover novel genotype-phenotype associations. GWAS offer a powerful tool for identifying genetic contributions to both common and rare diseases. At the same time, GWAS raise profound and challenging ethical questions. The most pressing questions derive from the likelihood that GWAS will uncover genetic information with the potential to be clinically meaningful to individual participants. As a result, investigators will inevitably face the question of whether individual genetic results from genome-wide scans should be disclosed to subjects. Commentators and ethics panels have addressed the question of whether genetic test results should be returned to research participants. Most policymakers advocate a cautious approach: disclosure should be limited to a narrow subset of results that meet stringent criteria related to magnitude of risk, severity of phenotype, and availability of prophylactic, therapeutic or reproductive interventions. Limited data regarding research participants'views, on the other hand, suggest a strong preference for disclosure of test results. However, because these data are based upon dichotomous responses to single questions, they do not address whether participants'views are sensitive to the factors identified by expert panels as salient to decisions about return of results. Without such information, it is impossible to know whether the gap between participants'views and policy guidance is as profound as the data suggest. The present proposal aims to bridge this gap through a factorial survey of 1800 members of the Jackson and Framingham Heart Studies, two influential cardiovascular cohort studies that conduct GWAS. Specifically, the proposed study will evaluate whether the criteria highlighted by policymakers are predictive of research participants'desires for this information. The study will also evaluate the relationships between attitudinal characteristics (e.g., views on and knowledge about genetics) and sociodemographic characteristics (e.g., age, education) and participants'desires for return of results. The findings will permit assessment of the extent to which there is concordance between the views of experts and those of research participants on this vexing topic. These data will help shape practice and policy regarding the return of individual results from genomic research.